Resistance device.



- No. 678,887. Patented July 23, IQOI.

' c. w. LARSON.

RESISTANCE DEVICE.

(Application filed Jan. 18, 1900.)

(No Model.)

V/itn eases. Inventor 7 2910' C vIW r 4mg" ar Mason ii ATEES FarmerCurios.

CARL l/V. LARSON, OF SCI-IENECTADY, NEYV YORK, ASSIGNOR TO THE GENERALELECTRIC COMPANY, OF NEW YORK.

RESISTANCE DEVICE.

SPECIFICATION forming part of Letters Patent No. 678,887, dated July 23,1901. Application filed January 18,1900. Eerial No. 1,847. (No model.)

To all whom it nut/y concern:

Be it known that I, CARL W. LARSON, a citizen of the United States,residing at Schenectady, county of Schenectady, State of New York, haveinvented certain new and useful Improvements in Resistance Devices,(Case No. 903,) of which the following is a specification.

This invention relates to an electric resistance device adapted to havean extraordinary large current capacity in proportion to its size.

Figure 1 is a perspective View, Fig. 2 a longitudinal section, and Fig.3 a transverse section, of one form of a device embodying the featuresof the inventiomof which other forms may be constructed withoutexceeding the limits of the invention.-

A is a support formed in a single piece of iron or other suitablematerial, preferably having a large capacity for heat. The sup port isformed with suitable projections or corrugations D to increase theheat-radiating surface.

B indicates resistance-conductors, such as rods of amorphous carbon,which are located in perforations in the support or casing A and areprovided with a thin sheath of incombustible insulation D, such as mica.This sheath is preferably about one thirty-second of an inch inthickness. The ends of the rods are incased in caps E, of conductingmaterial, such as copper, of any suitable construction, to which theline and interconnecting wires W are attached. The caps E are alsocovered with the sheath of mica. Other means for connecting the wires Wto the resistance-conductors may be employed, such as spreading out thecable and binding the ends about the conductor with a Wire. In any caseit is desirable to inclose the connecting means within aninsulating-sheath.

The rods B are held in the support A by means of a suitable plasticheat-conducting and electric insulating material F, such as a mixture ofPortland cement and sand or Portland cement alone, which is placed inthe enlargements G of the perforations in the sup port and when it setsholds the carbon rods securely in place and excludes air, thuspreventing deterioration of the carbon rods.

carbon rods provided at their ends with means for connecting them withthe outside leads, a thin sheath of incombustible heat-conducting andelectric insulating material surrounding said rods and connecting means,said parts being retained within abody of metal byasuitable plasticheat-conducting and electric insu lating material.

4. An electric resistance, which comprises a metallic body provided witha plurality of perforations, a carbon rod in each perforation, coppercaps on the ends of the rods, connecting-wires secured to the ends ofsaid caps,- a thin sheath of incombustible heat-conducting and electricinsulating material which surrounds the rods and caps, and a plasticheat-conducting and electric insulating material which surrounds thesheath and retains the rods in the perforation of the casing.

5. An electric resistance comprising ame tallic body provided withcavities, resistanceconductors in said cavities, and plastic materialadapted to secure said conductors within said cavities by mechanicallyinterlocking with said body.

l 6. An electric resistance comprising a metallic body having a largeradiating-surface, said body being also provided with cavities, each ofwhich has more than one diameter, carbon rods in said cavities, and aheat-conducting electric insulating cement filling the space betweensaid conductors and said body.

7. An electric resistance, which comprises carbon rods provided with athin sheath of incombustible heat-conducting and electrioinsulatingmaterial substantially as described, copper caps on the ends of therods, connectlug-wires secured to the ends of said caps, said rods beingretained within a body of metal by a suitable plastic heat-conductingand electric insulating material.

8. An electric resistance, comprising a metallic body provided with aplurality of perforations, a carbon rod in each perforation and havingreduced ends, copper caps having holes fitting the reduced ends, theouter surfaces of the caps being flush with the surfaces of the rods,connecting-wires secured in the ends of the caps, a thin sheath ofincombustible heat-conducting and electric insulating material whichsurrounds the rods and caps, and a plastic heat-conducting and electricinsulating material which surrounds the sheath and retains the rods inthe perforation of the casing.

9. A resistance device comprising carbon rods surrounded by a sheath ofincombustible electric insulation which is in turn surrounded andsecured Within a support by means of a plastic material.

10. An electric resistance comprising a metal casing,resistance-conductors in the easing, a thin sheath of mica surroundingeach conductor, and a material filling the spaces between theresistance-conductor and the easing, to insulate them from each other,convey heat from one to the other, hold the com ductors secure Withinthe casing, and exclude air from the conductors.

In Witness whereof I have hereunto set my hand this 16th day of January,1900.

CARL W'. LARSON.

Witnesses:

BENJAMIN B. HULL, MABEL E. JAcoBsoN.

